A solenoid operated valve is connected in series with a resistor and a PTC thermistor. Upon coil energization, the armature moves to close the valve member against a valve seat and further armature movement to close an air gap with a pole piece is absorbed by a spring between the armature and valve member. Upon closure of the air gap, the magnetic reluctance between the armature and pole piece is decreased such that significantly less current is required in the coil to hold the valve closed. Upon heating of the thermistor, the resistance is increased sufficiently to reduce the current to the hold-close level and less power is required thereafter to maintain the valve closed. The valve is applied to on-board vehicle diagnostic procedures performed after engine shut-down where current must be minimized to prevent battery drain to a level preventing re-start.